Outbreak of the South American tomato leafminer, Tuta absoluta, in the Chinese mainland: geographic and potential host range expansion

BACKGROUND: In 2017 Tuta absoluta was identified as an invasive species in China. Due to its rapid geographic expansion and the severe crop damage it causes, T. absoluta poses a serious threat to China's tomato production industry. To determine its geographic distribution and host range, intensive surveys and routine monitoring were conducted across the Chinese mainland between 2018 and 2019. The population colonization coefficient (PCC; ratio of colonized sites and prefectures) and population occurrence index (POI; ratio of infested host species and PCCs) were calculated. RESULTS: In northwestern China, T. absoluta populations established in Xinjiang exhibited a medium PCC value (similar to 0.03). In southwestern China, populations in Yunnan and its five neighboring provinces exhibited high (similar to 0.50 in Yunnan and Guizhou), or low (<0.02 in Guangxi, Sichuan, Hunan, and Chongqing) PCC values. In the Chinese mainland, infestations of four crop plant species (tomato, eggplant, potato, and Chinese lantern) and two wild plant species (black nightshade and Dutch eggplant) were identified; tomatoes were infested in every colonized province. Chinese lantern and Dutch eggplant are potentially novel hosts. Yunnan, Guizhou, and Xinjiang experienced the most serious damage (POI). In southwestern China, observed damage significantly decreased with increased distance from the first discovery site of T. absoluta to the farthest county of an infested province increased. CONCLUSION: T. absoluta populations are well-established and could potentially spread to other regions of China. The present study helps to inform the establishment of better pest management guidelines and strategies in China and tomato-producing regions worldwide. (c) 2021 Society of Chemical Industry.

Automated summary

The study found that Tuta absoluta populations in northwestern China's Xinjiang region exhibited a medium colonization coefficient, while populations in southwestern China's Yunnan and Guizhou regions had high colonization coefficients. The pest was found to infest four crop plant species and two wild plant species in China, with tomatoes being infested in every province with confirmed colonization. Damage severity was highest in Yunnan, Guizhou, and Xinjiang, and decreased with increasing distance from the initial discovery site of Tuta absoluta in southwestern China.